Lens-grinder.



G. H. FLAD.

LENS GRINDER.

APPLICATION FILED Nov. 9, 1908.

S14/vanto?,

HQML' NRL Patented Feb. 22, 1910.

Witneoom of lenses by enabling the RK, ASSIGNOR TO BAUSCH & LOMB OPTICAL GOTLIEB H. FLAI), OF ROCHESTER, NEW Y COMPANY, 0F ROCHESTER, NEW YO RK, A CORPORATION OF NEW YORK.

LENS- GRINDER.

Specification of ILetters Patent. Application led November 9, 190,8.

Patented Feb. 22, 13.9110.. Serial No. 461,607.

To all whom it may concern:

Be it knownn that I, Gorman I-I. FLAD, of Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Lens- Grinders; and I do hereby declare the following to be a full, clear, and exact description of the same, reference being had to the accompanying drawings, forming a part of this specification, and to the reference-m1- merals marked thereon. v

The present invention relates to lens grinders particularly of the type in Which a plurality of lenses are suitably supported and a grinding tool cooperates with the lenses -to give them their proper forms, and

vit has for an object to provide a construction which will reduce the cost of manufacture tools to be readily formed in the first instance and to be altered as may be required on account of Wear, thus dispensing` With the constant machining of the grinding tool Which is now required to keep it in proper condition.

To this and other ends the invention consists in certain improvements and combinations of parts all as Will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specification.

In the drawings, Figure l is a vertical section of the lens support and one embodiment of the grinding tool of a lens grinder: F ig. 2 is a section of a former which coperates With the grinding elements of the improved grinding tool to position them; Figs. 3 and 4t are vertical sections of two other embodiments; lFigs. and 6 are respectively a vertical section and a plan of another embodiment; and Figs. and 8 are respectively a plan and avertical section of still another embodiment.

Similar reference numerals indicate similar parts.

In grinding lenses it is customaryI to employ a grinding tool usually of metal'with a continuous surface accurately shaped by milling, turning, grinding or planing to give to the surface of the lenses the desired conformation and the tool is only useful for grinding the one particular surface for which it. was constructed because the abradant, as emery, is fed between this and the glass .t0 be ground and it is not intended that the surface of thegrinder should be fl g l I j t t plates the construction changed by use. The grinding surface however, loses its accuracy after a time and must be reshaped by substantially the same process used in forming it originally Which is expensive and requires considerable accurate Work.

M y invention broadly'considered, contemand use of a grindin;` tool embodying a holder and a plurality of separate grinding surfaces, a number of which are to be brought successively into contact with the material to be ground, said surfaces being adjusted in their holder by means of a former, pattern or templet and then secured firmly in position so that, eollectively, they will form a grinder having the shape of the pattern or templet and Will cause the material operated upon to be uniformly ground to the desired shape. It further contemplates such a construction of grinding tool formed in the manner and by the means indicated of such nature that when, by continued use, the grinder considered as a Whole, has lost its shape or curvature it may be readily restored and made. perfect again by a readjustment of the separated grinding elements or surfaces, employing ther same accurate former or pattern as before, said former or pattern therefore not being subjected to appreciable Wear.

In the embodiment of this invention illustrated in Figs. l and 2, there is employed a lens support preferably comprising a concave head l carrying a bed 2 of pitch or other ysuitable material in which the glass for the lenses 3 are embedded While the material is in plastic state. The head 1 may have a ball and socket connection 4 with an adjustable arm 5 that projects laterally from a shaft 6 serving to revolve the lens support.

The grinding tool in this form is convex and is` shaped to ,the surface it is desired to give to the lenses on the lens support. In the present instance it comprises a head or holder 7 detachably connected to the frame S and carrying a plurality of grinding elements 9 which are preferably in the form of separate disks of metal or other suitable material. These grinding elements 9 are ioo so arranged that the higher points thereof i form, collectively, the grinding surface having the desired configuration that is tobe given the lenses and they are when 1n use, rigidly secured to their holder, mdlcated by -7, but the connection therewith is of suoli a nature that they may be properly relatively positioned when the grinder is vformed,`by the use of a former or pattern readjusted in connection with the pattern or former. I find in practice that pitch is suitable for this purpose although metal or other material having a relatively lon1 melting point could be employed.

The form of the lens support and of the tool of course varies with the curvatures of the lenses to be formed, thus in Fig. 3 the grinding tool is concave and grinds a convex lens, in Fig. 4 the tool is shown curvedin one direction only and this is also true of Figs. 5 and 6 Where the curve of the grinding surface is opposite to that shown in Fig. 4., While in Figs. '7 and 8 the surface of the tool is flat.

With a tool constructed as described it is only necessary When the parts, such as the disks, Wear, to soften the material holding them and then reposition them preferably by the use of the pattern or former to conform to the desired surface to which the lenses are to be ground. The adjustment of the disksmay be obtained easily and quickly by any suitable device but it is `preferred to employ the pattern or former `10 which is accurately shaped to give to the lenses the desired surface; This former is ,adapted to engage the grinding faces of thegrinding lelements and shift the latter so that their highest points are properly positioned. The disks lie close together and When the grinder and the lenses are relatively moved with the abradant between them, the high points of the grinder Will' contact With all portions of the lenses and effectively grind the latter to the desired shape.

VFrom 4the foregoing it Will be seen that it is only necessary to employ one pattern or former l0 in the first instance for one curve as it is subjected to nofWearing or grinding action." The -grinding disks 9 may be reneWed when Worn out and the reshaping of the tool can be accomplished in a very short time and at a very small expense'.`v The disks or grinding elements are, of course, harder than the blanks to be ground, that 1s,

they have a greater resistance to abrasion than the lens blanks so that the Wear on said elements at each operation may be considered practically m'Z. rllhis is very important for the reason that the grinding surface of a machine of this kind at the beginning of the operation and at the en'd should not vary in any material degree for if it does it is impossible to grind the lenses to any definite surface or curve and', of course, unless they are so ground they are useless. The spaces between the grinding elements carry the abradant and evenly distribute it over all .the lenses rbeing ground.

The grinding surface (which, for convenience merely, arecalled disks, their configuration not being material) are relatively adjustable in the holder, in` the sense 'that their position in forming the grinder is capable of being accurately determined and they mayalso be rearranged When desired.

l claim as my invention:

1. A lens grinder comprising a lens support and a grinding. tool having a plurality of relatively adjustable grinding elements secured thereto to cooperate With. the lens blanks on the lens support, said elements being of material harder than the material being operated upon and constituting collectively a substantially lixed gage to determine definite shapes for-the lenses.

2. A lens grinder comprisingia lens support and a grinding tool embodying a holderA having a bed of relatively plastic material and a plurality of grinding elements supported on thefbed, said elements being of material harder lthan the material operated -upon and constituting collectively aasubstam tially fixed gage to determine definite shapes for'the lenses. A

'3. A lens grinder comprising a plurality of relatively radjustable grinding elements, and a bed. for said grinding elements of plastic material capable `of being softened,

said elements being of material-harder than the material to bev operated yuponand 'constituting 'collectively substantially 'fixed gage to determine definite shapes for the lenses. f o GOTLEB H. FLAD.

Witnesses:

F.. F. CHURCH, VWVM. G. WooDWoRT'HQ 

